Voltage and current regulator



Aug. 5, 1958 H. M. HUGE VOLTAGE AND CURRENT REGULATOR 2 Sheets-Sheet 1Filed July 30, 1953 26 2 1 CONTROL DEVICE FIGI FIG.3

INVENTOR.

H EN RY MARTIN HUGE ATTORNEYS Allg- 1958 H. M. HUGE VOLTAGE AND CURRENTREGULATOR 2 Sheets-Sheet 2 Filed July 30. 1953 NTROL DEVICE 27 Fl G. 5

IN V EN TOR.

HENRY MARTIN HUGE ATTORNEYS United States Patent Office 2,846,637Patented Aug. 5, 1958 VOLTAGE AND CURRENT REGULATOR Henry M. Huge, BayVillage, Ohio, assignor to Lorain Products Corporation, a corporation ofOhio Application July 30, 1953, Serial No. 371,225

13 Claims. (Cl. 321-25) This invention deals with a voltage and currentregulating device, and more particularly with a device in which arectified output voltage is closely regulated, under the control of abiasing current. My invention employs saturating magnetic cores havingimpedance windings which regulate the flow of rectified current andsaturating windings energized in part by load current and in part bycurrent from a source of uni-directional bias. As a source of constantbias current, in one embodiment of my invention I employ a voltageregulating circuit which is not sensitive to variations in inputfrequency nor input voltage, and which delivers a constant rectifiedcurrent to the saturating winding even though the resistance of thewinding may change with changes in temperature.

It is an object of my invention to provide a source of preciselyregulated rectified voltage whose potential is not affected by changesin alternating current input voltage, input frequency, ambienttemperature, or load current.

Another object of my invention is to provide a source of regulateddirect current especially suited for use as a standard voltage source ina larger control system.

Another object of my invention is to provide a source of regulateddirect voltage having an easily adjustable internal negative resistancecharacteristic, so that a constant voltage can be maintained across aload which is fed from the regulating device through a seriesresistance.

An additional object of my invention is to connect a control devicebetween a source of standard voltage and a load, and to produce in thesource of standard voltage a negative resistance characteristic whichwill neutralize the resistance of the control device so that the voltageacross the load remains constant in spite of variations in the currentpassed through the control device.

A still further object of my invention is to connect a control devicebetween a source of standard voltage and a load and to maintain aconstant voltage across the load even when the voltage drop across thecontrol device is a considerable fraction of the total voltage deliveredby the standard voltage source.

A still further object of my invention is to supply a constant biasingcurrent to a saturating reactor and to maintain the biasing currentconstant in spite of variations in input voltage, input frequency, andresistance of the biasing winding.

Another object of my invention is to connect a control device betweenthe source of standard voltage and the load and to maintain a constantvoltage across the load over a wide range of current through the controldevice, in both the positive and negative direction.

A still further object of my invention is to connect a control devicebetween a source of standard voltage and a load and to maintain constantvoltage across the load both when the standard voltage source isdelivering current and when it is absorbing current, and to limit themaximum current which the standard voltage source will absorb.

Another object of my invention is to provide a standard voltage sourcewhose output voltage can easily be changed in response to an externalsignal.

Other objects and a better understanding of my invention will beobtained by referring to the following specification and claims togetherwith the accompanying drawing, in which:

Figure 1 shows an embodiment of my invention in which a standard voltagesource comprising rectifiers regulated by impedance windings onsaturable magnetic cores furnishes direct current to load terminalsthrough a control device or resistance;

Figure 2 is a circuit diagram of a device similar to that of Figure 1,except that a single three-legged core structure is used in place of thetwo individual cores shown on Figure 1;

Figure 3 is the diagram of a biasing source which may be applied toFigures 1, 2, 5 and 6 and employing a ballast lamp;

Figure 4 is another alternate biasing source which may be applied toFigures 1, 2, 5 and 6 employing an alternating current voltage regulatorof a different type than that shown in Figure 1;

Figure 5 is a modification of Figure 1, in which the same windings areused both for biasing and impedance windings, and in which provision ismade for external adjustment of the output voltage by a separate signal;and

Figure 6 is still another modification of Figure 1, in which acenter-tapped transformer is employed, and the biasing and regulatingwindings are combined.

Voltage and current regulators embodying the features of. this inventionare particularly suited for use as a source of standard voltage in alarger control system such as that shown and described in my U. S.patent application Serial No. 780,408, filed October 17, 1947, and in myU. S. patent application entitled Regulated Rectifier, which is beingfiled concurrently with this application. In a device of this type, astandard voltage is balanced against a load voltage, with a controldevice, or

saturating winding, connected in series in the balancing circuit, sothat whenever the load voltage is different from the standard voltage acirculating current flows through the control device or saturatingwinding and afiects the operation of the main power source in such a wayas to restore the load voltage to its standard value. It can readily beseen that whenever current flows through the control device orsaturating winding, a difference in voltage will exist between the loadvoltage and the standard voltage. Therefore, if the standard voltage.actually is constant at all times, the load voltage will not remainconstant when a control current is flowing. In order to overcome thisdisadvantage, the standard voltage source employed in my applicationSerial No. 780,408 has an internal negative resistance characteristicwhich balances out the resistance of the saturating windings, so that aconstant voltage can be maintained across the load even when appreciablecurrent is flowing through the saturating windings.

To more fully explain the term negative resistance characteristic, itcan be stated that the output voltage of a voltage source having thischaracteristic will increase as the amount of load current delivered byit increases, and its voltage will decrease as its output currentdecreases. The voltage should preferably changeat a uniform rate, sothat a fixed value of negative resistance can be defined by the ratio ofthe change in output voltage to the change in output current.

By 'means of my present invention I am able to obtain a very uniformvalue of negative resistance over a wide range of load current, and amable to adjust the amount of negative resistance very readily over awide range of resistance values. Furthermore, I am able to obtain very.current operated controlling element.

high values of negative resistance without the loss of uniformity, sothat the voltage drop across the control device may be large, perhapsgreater than the load voltage,-without loss of regulation.

Because of the high value of negative resistance ob- .tainable with mypresent invention, it is adaptable to a wide variety of applications,such as the control of generator fields, and when used to controlsaturating reactors it may make possible considerable economies in thedesign of the reactors by relaxing limitations on the resistance of thesaturating windings.

In my invention, I also overcome one of the common defects encounteredin devices which employ a fixed biasing current to control a voltage. Indevices of this type, it is usually necessary to compensate in somemanner for changes in the resistance of the biasing windingsresultingfrorn changes in temperature. By my invention, I provide aconstant current source for biasing these windings so that compensationfor change in resistance is no longer necessary. This constant currentbiasing source is also unafiected by changes in line voltage and linefrequency. The details of operation can be explained more fully byreferring firstly to Figure 1.

The load current delivered by the arrangement of Figure 1 flows throughthe control device 26 to the load terminals 27 and 28. The controldevice may comprise saturating windings on one or more reactors, or afield winding of a generator or motor, or other type of direct Inparticular, the control device may regulate the output of another,perhaps larger, source of direct current which may supply current to thesame load to which terminals 27 and 28 are connected. Thus, whenever thevoltage across the load terminals drops, my direct current source willsupply greatly increased load current to the load and at the same timeactuate the control device as required to restore normal voltage acrossthe load. Alternatively, the control'device may be dispensed with, andthe load may .be taken directly across the terminals 61 and 28.

The direct current load terminals 27 and 28 are energized from. thealternating current source through rectifiers, 12, 13, 14 and 15 whichcomprise a full wave rectifier bridge having impedance windings 19 and20 in two of the arms of the bridge, in series respectively withrectifiers 12 and 13. Impedance windings 19 and 20 have saturablemagnetic cores 17 and 18. On core 17, windings 21 and 22 are used forbiasing purposes and windings 23 and 24 on core 18 serve the samepurpose. Windings 21 and 24 are connected in series with the loadcircuit and the load current flowing through them has a compoundingeffect, increasing the bias of the cores as the load increases.

A substantially constant biasing current is fed to windings 22 and 23 byrectifier bridge 32. The input voltage to rectifier bridge 32 isregulated by means of linear inductances 34 and 38 and saturableinductance 35. Because of the saturation of its core, the voltage acrossinductance 35 remains substantially constant over a wide range ofvoltage variations from source 10. Any slight tendency for the voltageacross inductance 35 to increase with increasing voltage from source 10can be corrected by properly locating the tap 36 on linear inductance34. In fact, this tap can be positioned to provide a reversecharacteristic, so that the voltage supplied to rectifier 32 diminishesas the voltage from source 10 increases. This characteristic may beuseful in compensating for the eftect of voltage variations from source10 on the regulating circuit comprising rectifiers 12, 13, 14 and 15 andimpedance windings 19 and 20.

Rectifier bridge 32 is energized from source 10 through linearinductance 38 and from tap 37 of linear inductance 34. By making thevoltage drop across inductance 38 --large incomparison with the voltageacross rectifier 32, .a constant current effect is obtained, so that theoutput cnrrenttof rectifier 32 is substantially unaffected by theresistance in its direct current circuit. Furthermore, by makinginductance 38 the major impedance in this circuit, the effect ofvariations in the frequency of source 10 on the current output ofrectifier 32 is substantially eliminated. The voltage drop acrossinductance 35 increases in direct proportion to the frequency of source10, and at the same time the impedance of linear inductance 38 increasesin direct proportion to the frequency of source 10. Consequently, thecurrent passed through inductance 38 and rectifier 32 remains constanteven though the frequency of source 10 may change considerably.

In order to prevent the ripple voltage from windings 22 and 23 frombeing fed back to rectifier 32, a filter choke 41 is inserted in seriesbetween rectifier 32 and saturating windings 22 and 23. The filtering iscompleted by the use of resistors 40 and 42 which efiectively preventripple voltage from the biasing windings from reaching rectifier 32.Resistors 40 and 42 are preferably proportioned so that the directcurrent passed through them is negligible in comparison with the directcurrent output of rectifier 32, in order that the constant currentcharacteristics of the circuit be preserved, and the effects ofresistance changes resulting from temperature changes in windings 21, 22and 23 may be eliminated. In order to adjust the output voltage, fineadjustment of the biasing current can be obtained by varying adjustableresistor 40 with the allowable limits. Further adjustment of the outputvoltage can be made with adjustable resistor 16..

Optimum regulation in the circuit of Figure 1 is obtained when the cores17 and 18 (and 35) are of gapless construction and when the corematerial is grainoriented steel or one of the alloys having asubstantially rectangular magnetization characteristic, such as Deltamaxor Orthonik. The results described herein can be obtained with ordinarystamped transformer laminations, but larger cores are required than withthe special core materials.

In the circuit of Figure 1, the windings are polarized so that thedirect current magnetization produced by windings 19 and 20 is oppositeto and no greater than that produced by windings 21, 22, 23 and 24. Thiscircuit provides a very precise current transformer characteristic, sothat the direct current ampere-turns produced by windings 19 and 20 willalways be exactly equal to the direct current ampere-turns produced bywindings 21, 22, 23 and 24.

The units 17 and 18 are preferably substantially identical, winding 19having the same number of turns as winding 20, winding 21 having thesame number of turns as winding 24, and winding 22 having the samenumber of turns as winding 23. If we represent the number of turns inwinding 23 by the figure N and the number of turns in winding 24 as Nthe turns in winding 20 as N and the currents through these windings asI I, and I respectively, the equation which characterizes the operationof this circuit is N l +N I =N I Representing the resistance of the loadresistor 16 as R and the combined resistance of windings 24, 21, and 25and element 26 as R the following equation also applies: (l I )R I R :E,where E is the voltage across the terminals 27 and 28.

From this it will be seen that when N :N (1+R /R then E=N R I /N Whenthis relationship is estab lished, E is therefore completely independentof I which is the load current deliveredto terminals 27 and 28.Furthermore, 1 can be either positive or negative without affecting thisrelationship, although I cannot be negative because of the limitationsimposed on it by rectifiers. This limitation automatically limits themaximtun negative value which I can reach. The ability of a standardvoltage source to operate with both positive and negative values of loadcurrent is a highly important feature in many cases, and is one of theadvantages impedance windings.

of my invention. At the same time, there are many cases, particularlywhere the standard voltage source is used to control saturable reactors,where the amount of reverse current absorbed by the standard voltagesource should be limited to prevent reverse saturation of the controlreactors and a consequent abnormal operating condition.

By my invention, I am able to limit the value of reverse current toalmost any desired value simply by suitable adjustment of resistance 16(R The load current delivered by the arrangement of Figure 1 flowsthrough the filter inductance 25' and control element 26 to the loadterminals 27 and 28. As previously mentioned, element 26 may comprise acontrol device, such as the field of a generator or a series ofsaturating windings on saturable reactors in a larger regulatedrectifying arrangement, which also supplies load to terminals 27 and 28.On the other hand, the rectifying arrangement of Figure 1 can be used tosupply load current directly to a load, in which case, resistance 26' isno longer in the circuit, and terminals 61 and 28 become the loadterminals. Omission of the resistance 26 can readily be compensated byreducing the number of turns on the compounding windings 21 and 24.

' The circuit arrangement shown in Figure 2 operates in essentially thesame manner as that shown in Figure 1. The chief ditference between thecircuit of Figure 2 and that of Figure 1 is that the impedance windings19 and 20 in Figure 2 are wound on a three-legged core structure, sothat a single biasing winding 23 can readily embrace both of the fiuxpaths for the two impedance windings 19 and 20 and a single compoundingwinding 24 likewise can embrace the flux paths of both of the The smallarrows shown by each winding in Figure 2 indicate the direction of thedirect current flux produced by that winding. It will be noted that theimpedance windings 19 and 20 produce flux which is opposite to thatproduced by the biasing winding 23 and the compounding winding 24. Thisis the same relationship as explained in connection with Figure 1, andprovides the type of operation outlined in connection with Figure 1.

The source of biasing current connected to terminals 30 and 31 in Figure2 is represented simply by a battery 11 inseries with an adjustableresistor 29 in place of the voltage regulated rectifier shown inFigure 1. Where a steady source of direct current is available, thebiasing circuit of Figure 2 can readily be substituted for that ofFigure 1. In order to compensate for the effect of voltage variationsfrom source on the current passed through impedance windings 19 and 20,I have found that the use of input voltage compensation is sometimesrequired. This is accomplished in Figure 2 by the use of rectifierenergized from transformer 62. The output current of rectifier 60increases as the voltage of source 10 increases, thereby increasing thevoltage drop across resistor 29 and consequently reducing the biasingcurrent through winding 23 as the input voltage of source 10 increases.In this manner I am able to reduce the bias of the core 32 at a ratejust sufiicient to compensate for the effect of increasing input voltageon this circuit. As previously mentioned, the circuit of Figure 1 has asimilar feature available in the use of tap 36 on inductance 23 whichcan be used to reduce the bias as the voltage from source 10 increases.When gapless cores of rectangular magnetization characteristics are usedfor cores 17, 18 and 32, this expedient may not always be necessary.

Two other alternative methods for obtaining biasing current are shown inFigures 3 and 4. In Figure 3, the rectifier bridge 32 energized fromsource 10 passes current through a ballast lamp 33 and adjustableresistor 29 to terminals 30 and 31 which are numbered to correspond withterminals30 and 31 in the other figures. The ballast lamp maintains aconstant biasing current in spite of the variations in the voltage ofsource 10,

and the reverse characteristic previously mentioned can also be obtainedwith this circuit. The ripple current produced across terminals 3tt and31 can be used to increase the temperature of the ballast lamp 33 as thevoltage of source 10 increases to a sufiicient degree to actually causea reduction in bias current with an increase in input voltage. I havefound that the application of the biasing arrangement shown in Figure 3to the circuits shown in Figures 1, 2, 5 or 6 can be made to exhibitthis characteristic sufliciently to permit the use of ordinarytransformer laminations for the cores 17 and 18 or 32 in these figures.

The biasing circuit shown in Figure 4 employs a more conventional typeof voltage regulator having a saturable core 39 energized from source 10by primary winding 46, and having secondary Winding 50 with capacitor 48connected across it. Leakage shunts 51 separate the primary andsecondary windings, and a compensating winding 47 together with tap 49completes the output circuit which feeds power to rectifier bridge 32.This type of regulating circuit compensates for changes in the voltageof source 10 and delivers a constant voltage to terminals 30 and 31. Afilter circuit comprising inductance 41, resistor 40 and capacitor 52prevents ripple current from being fed back into terminals 30' and 31where it would be rectified by rectifier 32 and aiiect the regulation.

It will be noted that a filter capacitor 52 is used in Figure 4 in placeof the resistor 42 in Figure 1. These arrangements can be usedinterchangeably and the choice is one primarily of designconsiderations. It should be pointed out that the regulating circuit ofmy invention will work equally well with either a high impedance or lowimpedance biasing source. The circuits shown in Figures 1 and 4 areessentially low impedance biasing sources, those of Figures 2 and 3 maybe either high or low, whereas the circuit shown in Figure 5 has a highimpedance biasing source, as the inductance 41 is connected directly inseries with the biasing windings.

In the circuit of Figure 5, the same windings are used for two purposes;that is, windings 19 and 20 are used both for impedance windings andbiasing windings. They are provided with taps 43 and 44 to permit theuse of different numbers of turns for the two functions, although itwill be apparent that the entire winding can be used for both purposeswhenever proper circuit values are available.

In Figure 5, as in Figures 1 and 2, rectifier element 12 is in serieswith impedance winding 19, and rectifier element 13 is in series withimpedance winding 20. However, the alternating current lead from source10 goes directly to the junction between impedance windings 19 and 20 inFigure 5 instead of to the junction between rectifiers 12 and 13 inFigure 1. Actually, this is just a reversal of the relative positions ofthe rectifier and impedance winding in the series circuit and does notafiect the operation.

The compounding windings 21 and 24 in Figure 5 are connected between thepositive rectifier terminals and the load terminal 27, as in the Figures1 and 2. The negative terminal 28 is connected directly to the negativerectifier terminal. In Figure 5, an adjustable resistor 45 is connectedin series with the direct current output of the rectifier, this resistormay be added to any of the other circuits, and can be used to adjust theregulating characteristics of the circuit, in other words to adjust thepositive resistance of the circuit to equal the negative resistancecharacteristic produced by the regulating arrangement.

When the biasing source has a high impedance as in Figure 5, the voltagewave shape supplied to terminals 27 and 28 has considerably lessalternating current component than when the biasing source has a lowimpedance, and the filter choke 25 shown in Figures 1 and 2 is omittedin Figure 5. However, in many cases, the deciding factor in determiningwhether or not the filter choke 25 can be omitted lies in the amount ofripple voltage produced from other sources across the load terminals 27and 28 or produced in the control element 26. If appreciable ripplevoltage appears from either of these two sources, it will generally benecessary to use a filter choke 25 in order to prevent rectification ofthe ripple voltage by the rectifiers 12, 13, 14 and 15.

In Figure 5, windings 53 and 54 have been added to the saturable cores17 and 18 and connected to terminals 55 and 56. These terminals are tobe energized from an external signal to modify the output voltageappearing across terminals 27 and 28, to provide remote manual control,load limiting characteristics, as in my prior application Serial No.780,408, or other automatic control features such as those knownanddescribed in my patent application entitled Regulated Rectifier whichis being filed concurrently with this application. In the circuit ofFigure 6, a center-tapped transformer 59 is used and the compoundingwindings are combined with the biasing windings, but the essentialoperating features of the previous circuits are maintained. The halfwave rectifier 12 is in series with impedance Winding 19 and the halfwave rectifier 13 is in series with impedance winding 20 as in Figures1, 2 and 5.

The biasing windings 22 and 23 are provided with taps 57 and 58 by meansof which the correct number of turns required for compounding are madeavailable. The relative polarities of the windings are the same inFigure 6 as in the previous figures, and the operating features are thesame. Figure 6 is similar to Figure in that it shows a high impedancebiasing source with the inductance 41 connected in series with thebiasing windings.

In the circuits of Figures 5 and 6 where the same windings are used fortwo purposes, the circuit equations used for Figure 1 no longer strictlyapply, but the corrections which have to be applied to make themproperly describe the operation of Figures 5 and 6,are of a linearnature and do not destroy the essential properties of my invention.

Although I have described my invention as applied particularly to anapplication in which it serves as a standard voltage source to be usedto operate a control device connected between it and load terminals forthe purpose of maintaining constant voltage across the load terminals,it will be apparent that my invention may also be applied as a completeunit in itself for the provision of a regulated voltage or current.Furthermore, the various features shown and described in the severalembodiments of my invention depicted herein are in generalinterchangeable between the various figures and numerous modificationsknown to those skilled inthe art may be applied without departing fromthe spirit and scope of my invention as hereinafter claimed.

I claim as my invention:

1. Means for energizing a direct current'control device comprising incombination, direct current'load terminals connected to alternatingcurrent input terminals through rectifying means comprising a pluralityof rectifying elements, a plurality of saturable magnetic flux paths,biasing winding means embracing said flux paths, means for supplying asubstantially constant unidirectional current to said biasing windingmeans to magnetize said flux 'paths, a-plurality of impedance windings,one embracing when current flows from said rectifying elements to saidload terminals;

2. Means for energizing a direct current controldevice, comprising incombination, direct current'load terminals connected to alternatingcurrent input terminals'through rectifying means comprising a pluralityof rectifying elements, a plurality of saturable magnetic flux paths,means for impressing on saidflux paths a substantially constantunidirectional magnetizing force to magnetize said flux paths, aplurality of impedance windings, one embracing each of said flux paths,each of said impedance windings being connected in series with one ofsaid rectifying elements, whereby said flux paths are demagentized bycurrent flowing through said rectifying elements, a resistance elementenergized with rectified currentfrom said re'ctifying elements,compounding winding means embracing said flux paths, direct currentcircuit means extending between said resistanceelement and said loadterminals and including the compounding winding means andsaid directcurrent control device in series, said compounding winding means beingpolarized to magnetize saidflux paths when current flows from saidrectifying elements to said load terminals.

3. A regulating arrangement having alternating current input terminalsand direct current load terminals and comprising in combination, asaturable magnetic core structure having first, second and third coremembers, first and second substantially equal windings on said first andsecond core members respectively, third and fourth windings on the thirdcore member, a plurality of rectifying elements, a resistance element,circuit means for supplying rectified current to said resistanceelement, said circuit means extending from said input terminals to saidresistance element and including said rectifying elements and said firstand second windings, one of said elements being in series with each ofsaid two windings, whereby said windings are energized by alternatehalf-cycles of alternating current from said input terminals and impressadditive unidirectional magnetizing forces across saidthird core member,means for supplying direct current to said third winding to produce insaid third core member a magnetizing force opposite to saidunidirectional magnetizing forces, and a direct current circuitextending from said resistance element to said load terminals throughsaid fourth winding.

4. A regulating arrangement having alternating current input terminalsanddirect' current load terminals and comprising in combination, asaturable magnetic core structure having first, second and thirdcoremembers, first and second substantially equal windingson said firstand second core members respectively, third and fourth windings on thethird core member, a plurality .of rectifying elements, a resistanceelement, circuit means for supplying rectified current to saidresistance element, said circuit means extending from said inputterminals to said resistance element and including said rectifyingelements and said first and second windings, one of said rectifyingelements being in series with each of said two windings whereby saidwindings are energized by alternate halfcycles of alternating currentfrom said input terminals and impress additive unidirectionalmagnetizing forces across said third core member, means for supplyingdirect current to said third winding to produce in said third coremember a magnetizing force opposite to said unidirectional magnetizingforces, and a direct current circuit extending from said resistanceelement to said load tenninals through said fourth winding, said fourthwinding being polarized to aid said third winding, the turns in saidwindings being in substantially the ratio where N, is the number ofturns in the fourth winding, N the number of turns in each of the firsttwo windings, R is the resistance of said resistance element and R isthe resistance of said direct current circuit.

5. A regulating arrangement having alternating current input terminalsand direct current load terminals and comprising. in combination, firstand second substantially equal saturable magnetic cores, a first, asecond and a third winding on each of said cores, corresponding windingson the two cores having a substantially equal number of turns, aplurality of rectifying elements, a resistance element, circuit meansfor supplying rectified current to said resistance element, said circuitmeans extending from said input terminals to said resistance element andincluding said rectifying elements and said first windings, one of saidrectifying elements being in series with each of said first windings,whereby said first windings are energized by alternate half cycles ofalternating current from said input terminals, means for supplyingdirect current to said second windings in series to produce in saidcores magnetizing forces opposite to those produced by the firstwindings, and a direct current circuit extending from said resistanceelement to said load terminals through said third windings in series,said third windings being polarized to aid said second windings.

6. A regulating arrangement having alternating current input terminalsand direct current load terminals and comprising in combination, firstand second substantially equal saturable magnetic cores, a first, asecond and a third winding on each of said cores, corresponding windingson the two cores having a substantially equal number of turns, aplurality of rectifying elements, a resistor, circuit means forsupplying rectified current to said resistor, said circuit meansextending from said input terminals to said resistor and including saidrectifying elements and the said first windings, one of said rectifyingelements being in series with each of said first windings, whereby saidfirst windings are energized .by alternate half cycles of alternatingcurrent from said input terminals, means for supplying direct current tothe said second windings in series to produce in said cores magnetizingforces opposite to those produced by the rectified current through thefirst windings, and a direct current circuit extending from saidresistor to said load terminals through said third windings in series,said third windings being polarized to aid said second windings, theturns in said first and third windings being in substantially the ratioN /N =1+R R where N is the number of turns in the third winding, N isthe number of turns in the first winding, R is the resistance of saidresistor and R is the resistance of said direct current circuit.

7. In combination with a rectifying arrangement hav ing saturablemagnetic core means, with impedance winding means, biasing winding meansand compounding winding means thereon and having rectifying elementsserially connected between alternating current input terminals anddirect current load terminals through said impedance Winding means andsaid compounding winding means, means for energizing said biasingwinding means, comprising in combination, a saturable inductance elementand a first linear inductance element connected in a series circuitenergized from said input terminals, a second linear inductance elementand a full-wave rectifier connected in series in a circuit substantiallyin parallel with the saturable inductance element, and a direct currentcircuit extending from said full-wave rectifier to said biasing windingmeans.

8. A regulating arrangement having alternating current input terminalsand direct current load terminals and comprising in combination firstrectifying means comprising a plurality of rectifying elements, magneticcore means having a plurality of saturable flux paths, biasing windingmeans embracing said flux paths, second rectifying means connected tosaid biasing winding means to supply current thereto and magnetize saidflux paths, a plurality of impedance windings, one embracing each ofsaid flux paths, one of said rectifying elements being in series witheach of said impedance windings, a resistance element energized withrectified current from said, lf'cf tifying elements, compounding windingmeans embracing said flux paths, a direct current circuit extending fromsaid resistance'element to said loadte'rminals through said compoundingwinding means, a first alternating current circuit energized from saidinput terminals and comprising first and second substantially linearinductances in series with each other and with said second rectifyingmeans, and a second alternating current circuit energized from saidinput terminals and comprising a saturable-inductance in series with at'least a portion of said first linear inductance.

9. In a circuit, the combination of a transformer having a saturablemagnetic core, with first, second, and third windings thereon, aresistive circuit element, a rectifying element in series with the firstwinding and the resistive element, means for exciting the rectifyingelement, the resistive element and the first winding from an alternatingcurrent source, means for supplying direct current to the secondwinding, a direct current load circuit connected to said resistiveelement through said third winding, the turns in said first and thirdwindings being in substantially the ratio N /N =1+R /R where N is thenumber of turns in the third winding, N is the number of turns in thefirst winding, R is the resistance of said resistive element, and R isthe resistance of said direct current circuit.

10. A regulating arrangement having alternating current input terminalsand direct current load terminals, and comprising, in combination,saturable magnetic core means having first, second, and third windingmeans thereon, a rectifying element, a resistive circuit element, firstcircuit means for energizing the resistive circuit element from theinput terminals through the first winding means and the rectifyingelement, means for supplying direct current to the second winding means,and a direct current load circuit extending from the resistive elementto the load terminals through the third winding means, the first andthird winding means having turns in the ratio N /N =1+R /R Where N isthe number of turns in the third winding, N is the number of turns inthe first winding R is the resistance of said resistive circuit element,and R is the resistance of said direct current load circuit.

11. A regulating arrangement having alternating input terminals anddirect current load terminals, and comprising, in combination, saturablemagnetic core means having first and second magnetic paths, firstwinding means on said magnetic core means, said Winding means having afirst portion inductively related to said first flux path and having asecond portion inductively related to said second flux path, a resistor,first and second rectifying elements, first circuit means for energizingthe resistor from the input terminals through the first portion of thefirst winding means and the first rectifying element, second circuitmeans for energizing the resistance from the input terminals through thesecond portion of the first winding means and the second rectifyingelement, second winding means on said magnetic core means having turnsinductively related to both of said flux paths, means for supplying adirect current to the second winding means, third Winding means on themagnetic core means inductively related to both of said flux paths, anda direct current load circuit extending from the resistor to the loadterminals through the third winding means, the turns on each. of saidflux paths being substantially in the ratio- N /N =1+R /R where N is thenumber of turns in the third winding means, N is the number of turns in.the first winding means, R is the resistance of said resistor, and R isthe resistance of said direct current circuit.

12. A regulating arrangement having alternating cur rent input terminalsand direct current load terminals and comprising in combination,saturable reactor means: having impedance winding means and saturatingwinding means, means for impressing a substantially constant bias: onsaid saturable reactor means, a resistor, first rectifyingmeansf'cqnnected in serieswith ,s'aid impedance winding meansbetweenkthej input terminals and the. resistor. wherebyfpulsatingcurrent is passed. through said impedance winding means tomagnetize said reactor means in opposition'toj said bias, and means forconnecting said load terminals across said resistor through saidsaturating winding means whereby load current flowing through saidsaturating winding means magnetizes said reactor means in addition tosaid bias.

13. A regulating arrangement having alternating current input terminalsand direct current load terminals and comprising in combination,saturable reactor means having impedance winding means and saturatingwinding means, means for impressing a substantially constant bias onsaid saturable' reactor means,,a resistor, first rectifying meansconnected in series with said impedance winding "12 a means between theinput terminals andthc; resistor, find means for connectingsaidloadterminalsacrossssaid resistor through said saturating windingmeans-whereby load current flowing through said saturating meansmagnetizeshsaid reactor meansfin-addition-to-said bias.

*References Cited in the'file-of this patent UNITED STATES PATENTS LammJuly v9, 1946 2,525,451 Graves Oct. 10,,1-950 2,606,314 Potter Aug. 5,1952 2,611,889 Huge Sept.,23,,1952 2,622,239 I Bracutt 'Dec.'16, 1952 152,653,293 Huge ,Sept. 22,1953

